B.,
Goodness! I read this right after I dropped my 5 year old at VBS lol. Fortunately my aunt is his group leader and he has a cousin in his group, so I feel ok!
I would talk to your daughter about what happened. The same thing happened when my son was 3 about a month before he turned 4. He loved going to daycare and playing with the kids. Then one day, he started having freak outs when I would take him. It lasted about a week. He would scream and cry for me not to go, and it was awful. I had to leave to take him 10 minutes earlier, JUST so I can give him extra hugs before I left. One day I went to take him and I saw the 2 school age boys pushing a 2 year old girl around! As soon as I walked in and saw that the teacher saw and went over there, but it clicked in my head. The school age kids were in there with the toddlers before school sometimes and I had just witnessed them picking on a kid??? Is that what is going on with my son? So I spoke with the teacher and she said that some of the big kids had been mean to the younger ones and they had plans to separate them again the next day. They had someone quit unexpectedly, so the kids were split up and distributed between classes before the bus came. I talked to my son and asked him if the big kids were mean to him, and he said yes they pushed him down and they took his toys and they made his friends cry. The next day when I took him there were no big kids in the room and I pointed that out to him. He still cried and clung to me, but he stopped that after a few days of being "big kid free". You should talk to your daughter about what happened. Someone might have been mean to her, so now she associates that with church.
He also did the no Sunday school thing with my mom. If she took him to church, he would pull away and refuse to go. Grandma would take him in the family room with her so she could hear the message, but it was distracting. That was all about the will power struggle. I know that lasted a few months before finally she told him he had to go to class, or she wouldn't take him to church anymore. That meant he couldn't go to her house and spend the night! That changed his mind!
With the nights, I too experienced that with my son. He didn't get hysterical, but he would cry that he didn't want to be alone. He was 4, and it was around the time his little sister was born. First it was he wanted me or dad, then it was just mom, then he went through a phase of just dad. He said he was scared to be all alone (by this time I had became a full time SAHM). We started a ritual every night that after he would get tucked in, I would turn on his night light and stand outside his open door. I would call out his name and ask if he could hear me. Then I would go farther and ask. After I got to the living room I would call to him again. For awhile, he would call for me and I would go back to the door and tell him I was right there. After he settled down, dad and I took turns checking on him till he fell asleep. He knew we were there and that made him feel better.
The best thing is to really talk to her and try to figure out what happened. It could have been a mean kid, a different teacher than her Sunday school, or even the teacher was harsh with her. Something happened. Make sure she knows that even at church you can be there. Possibly volunteer for her class a couple times? Its a drag for you but you can see the other kids and the way they interact. Once you think you have it figured out, try again to leave her. Good luck!
V.